Audio 5:02
Myrtle rust spreads along east coast

Timothy McDonaldUpdated
Tue 13 Mar 2012, 7:04 AM AEDT

An invasive tree disease called myrtle rust has the potential to infect hundreds of native Australian plant species, and could cause significant economic and environmental damage. One advocacy group says the Federal Government bungled the response to its arrival in Australia, and the failure to stop its spread should be a wake-up call.

Transcript

One of the newest is myrtle rust, a tree disease that's spreading rapidly up and down the east coast of Australia.

One advocacy groups says its arrival in Australia should serve as a wake-up call to governments to overhaul its procedures for halting invasive species.

Timothy McDonald has our report.

TIMOTHY MCDONALD: The Central Coast of New South Wales is where myrtle rust was first discovered in Australia.

Dr Angus Carnegie is a senior research scientist with New South Wales Department of Primary industries.

He's monitoring a patch of box turpentine trees at the end of a dirt track in the Olney State Forest, north of Sydney, where conditions at the moment are ideal for the rust.

ANGUS CARNEGIE: It needs this sort of nice, moist weather - leaf wetness and good temperature are really good conditions for the rust, but to help it spread it actually needs dry conditions so if you have...

ANGUS CARNEGIE: There's a few more of those coming along. If you have nice weather like we've had in the last couple of days in Sydney and then you get a string of really nice hot days, then you can get the rust developing and producing a lot of spores, a lot of pustules.

TIMOTHY MCDONALD: Myrtle rust originated in South America, where it probably evolved as part of a wider ecosystem and therefore didn't pose much of a threat to local species.

But it's been on the radar as a potential problem for some time, because it did have a significant impact on eucalyptus plantations there.

Spores of the strain that's now in Australia most likely came in from Hawaii, maybe on the bottom of a pallet or possibly on someone's hiking boot - nobody really knows.

But the impact could be huge because hundreds of Australian native species are susceptible to the rust, which infects and often kills off new leaves.

Angus Carnegie says Myrtle Rust is here to stay, and the best the authorities can hope for now is to try to manage the problem.

ANGUS CARNEGIE: These old leaves that have been sitting on here for 12 or more months, they'll eventually drop off and all these new leaves are getting severely diseased and they die as well.

And so if you look at this tree here, it might have 50 leaves on it, 100 leaves on it. The one behind us has several thousand. And this is what we're trying to do here is compare the impact of the disease on a tree that has the disease and one that doesn't have the disease.

And one of the things we're trying to look at here also is these trees that are severely diseased, do they flower, and therefore fruit, and then provide for the next generation of seedlings?

TIMOTHY MCDONALD: And do we have an indication one way or the other yet?

ANGUS CARNEGIE: No, we don't. We know that the fruit and flower are infected and Geoff Pegg, a colleague in Queensland, has been monitoring fruit infection of rhodamnia up there. And what happens is the fruit gets infected and it's prematurely dropped.

So one of the things that we're hoping to look at is seeing how widespread that is, is there any viable seed within those fruit capsules and things like that.

TIMOTHY MCDONALD: And is this something that's going to have a flow on affect to animals as well?

ANGUS CARNEGIE: Well that's potential, so what then replaces, you can see here as we're standing around just looking around us here within a sort of 10 metre radius there's several hundred of these plants here. So it's quite a dense understorey here.

If this all dies out, what replaces it? Is it a weed like lantana? Is it another native rainforest species? And what are the flow on effects from the fauna - vertebrates and mammals, birds - that use the fruit and the flowers?

He says the fact that the rust attacks freshly sprouted leaves suggests it could be a very serious problem for koalas.

MATTHEW CROWTHER: Attacking young leaves and basically getting rid of them is of particular concern - not just to the short term of the koalas eating those leaves but in the long term for the viability of that plant to support koalas.

TIMOTHY MCDONALD: And there's potential for economic impact as well.

Anthony Kachenko is the environmental and technical policy manager for Nursery and Garden Industry Australia.

ANTHONY KACHENKO: We don't have data to actually pinpoint how much it has in fact cost the industry as a whole. However, there are cases where individual growers, for example, have invested up to $50,000 in new spray rigs.

TIMOTHY MCDONALD: One advocacy group says the authorities knew of its effect on South American plantations for years before its arrival here so they should have seen myrtle rust coming.

JOHN DEJOSE: We knew in advance that this was going to be the equivalent of a nuclear bomb for the Australian ecosystems.

TIMOTHY MCDONALD: That's CEO John DeJose from the Invasive Species Council.

JOHN DEJOSE: We just cannot understand the decision after only one week to declare the Myrtle Rust ineradicable. And in the event this was a decision that was reversed, and then reversed again.

We can't get any straight answers out of the Department of Agriculture, Fisheries and Forestries about the myrtle rust incursion response. They don't seem to want to talk about it. We think that there is a review needed.

TIMOTHY MCDONALD: The World Today approached the Department of Agriculture, Fisheries and Forestry for a response. The department didn't provide comment.